RADIX IPECACUANHiE. IPECAC. IO9 



varies, a point which, according to Tschirch, is of im- 

 portance. The average diameter of the starch grains is 

 from 7 to 9 microns ; some of the larger granules may- 

 measure from 1 7 to 1 9 microns. Kraemer gives 4 to 7 . The 

 smallest are usually about 2 microns. The starch of 

 Carthagena ipecac is said to range on the average larger 

 than that of Rio ipecac. Schneider's figures are from 

 17 to 23 micron^. 



The crystals are of the acicular variety, usually lying 

 in special cells, but in the powder dislodged therefrom 

 they range in length from about 20 to 100 microns, though 

 this only represents an average. 



The cork cells are dark brown, and without clearing 

 are usually indistinct in outline; in size the cells range 

 from 9X15 to 15X25 microns. 



The parenchymatic cells of the cortex form a large part 

 of the powder. The cells are usually ample, ranging 

 from 60 to 100 microns. They are comparatively thin- 

 walled, and are usually filled with starch grains. Some 

 few special cells of the parenchymatic sheath contain 

 the acicular crystals of calcium oxalate. 



The remaining elements of the powder present an 

 interesting series of gradations in cell structure. In some 

 works they are called tracheids, yet there would seem to 

 be enough characters to differentiate wood-fibre like 

 tracheids, true tracheids, and vessel-like tracheids. 

 Schneider describes at least six kinds of tracheids.* 



The most characteristic cell forms are: (i) Vessel- 

 like tracheids, having large openings, usually at the end 

 of diagonal cross walls ; these are usually the largest tra- 

 cheids, from 12 to 15 microns in diameter. (2) Tracheids 

 with bordered ]X)res ; usually smaller and having no end 

 opening. (3) Ersatzfasem, or wood-fibre-like tracheids, 

 with diagonal pores ; these elements are about 1 5 microns 

 in diameter and about 300 microns long. 



♦Journal of Pharmacology, vol. 4, 1897. p. 3. 



